JP2001140918A - Elastic shaft coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of fully assuring the vibration absorption performance of an elastic material which constitutes a shock-absorbing tube. SOLUTION: A plurality of recesses 24 and 24 are provided in both axial end faces of the elastic material 10a. Thereby the rigidity of the elastic material 10a is appropriately reduced so that the elastic material 10a is free to fully absorb vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION An elastic shaft coupling according to the present invention is incorporated, for example, into a universal joint which constitutes a steering device for an automobile, so that the movement of a steering wheel can be freely transmitted to a steering gear, and vibration on the steering gear side is reduced by the steering. Prevents transmission to the wheel.

[0002]

2. Description of the Related Art A steering apparatus for an automobile is configured to transmit the movement of a steering shaft rotated by a steering wheel to a steering gear and to impart a steering angle to front wheels. Usually, the steering shaft and the input shaft of the steering gear cannot be arranged on the same straight line. Therefore, a universal joint is provided between the steering shaft and the input shaft so that the movement of the steering wheel can be transmitted to the steering gear. In addition, to prevent the vibration transmitted from the wheels to the steering gear when the car is traveling, further transmitted to the steering wheel and give the driver discomfort, an elastic shaft coupling with vibration absorption capacity is provided in the middle of the steering shaft. Conventionally, the universal joint has a vibration absorbing ability. In order to provide the universal joint with the vibration absorbing capability, it is common practice to incorporate an elastic material such as rubber into the universal joint and to prevent transmission of vibration by the elastic material.

The above-mentioned elastic joint or a universal joint incorporating the elastic joint has been disclosed in Japanese Patent Laid-Open No. 61-20 / 1986.
Japanese Patent Application Laid-Open Nos. 1924, 8-170647, 5-89964, 7-43494, and French Patent Publication 2614985 are known. FIGS. 4 and 5 show Japanese Unexamined Patent Publication No.
This shows a structure similar to that described in Japanese Patent No. 170647.

As shown in FIG. 4, a universal joint 1 incorporating an elastic shaft joint shown in FIGS. 4 and 5 has a cylindrical shaft 2 and a distal end portion of the shaft 2 (a left end portion in FIG. 4). First yoke (cylindrical member) 4 externally fitted and fixed via a buffer cylinder 3
, A second yoke 5, and a cross shaft 6 connecting the second yoke 5 and the first yoke 4. The shaft 2, the buffer cylinder 3, and the first yoke 4 constitute an elastic shaft coupling 7. A flange-shaped transmission piece 8 having a shape as shown in FIG. 5 is provided on a portion protruding from one end edge (left end edge in FIG. 4) of the buffer cylinder 3 at a tip end of the shaft 2 by cold forging or the like. It is formed integrally with the shaft 2 by an appropriate processing method. Protrusions 9, 9 protruding diametrically outward from the outer peripheral surface of the shock-absorbing cylinder 3 are provided at two positions on the outer peripheral edge of the transmission piece 8 on the opposite side in the diameter direction.

[0005] The cushioning cylinder 3 is formed in a cylindrical shape including an elastic material 10 such as an elastomer such as rubber. That is, in the shock-absorbing cylinder 3, the inner sleeve 11 and the outer sleeve 12, each made of metal and made in a cylindrical shape, are arranged concentrically with each other. Then, the outer peripheral surface of the inner sleeve 11 and the inner peripheral surface of the elastic member 10 are joined by baking or bonding or the like, and the inner peripheral surface of the outer sleeve 12 and the outer peripheral surface of the elastic member 10 are similarly joined. ing. Then, the inner sleeve 11 is externally fitted and fixed to the tip of the shaft 2, and the outer sleeve 12 is fixed to the first yoke 4.
And is internally fitted and fixed to a cylindrical portion 13 described below.

The first yoke 4 has a pair of a cylindrical portion 13 and a pair extending in the axial direction from a position diametrically opposite one end (left end in the figure) of the cylindrical portion 13 in the axial direction (left-right direction in FIG. 4). And the first arms 14, 14. First circular holes 15, 15 are formed concentrically with each other at the distal ends (left ends in FIG. 4) of the first arms 14, 14, respectively. Notches 16, 16 are formed at portions of the cylindrical portion 13 opposite to the pair of first arms 14, respectively, at positions diametrically opposite to one end in the axial direction. The width W of each of the notches 16 is greater than the width w of the protruding pieces 9 of the transmission piece 8 (W> w). Then, in a state where the shaft 2 is attached to the inside of the first yoke 4, each of the protruding pieces 9, 9
16 and loosely engage with the gap. In the case of the illustrated example, the protruding pieces 9, 9 and the notches 16, 16 constitute a stopper portion.

The second yoke 5 has a pair of second arms 17, 17 which are provided separately from each other, and can be connected and fixed to the end of another shaft (not shown).
In addition, second circular holes 18 are formed at the distal ends of the second arms 17, 17 concentrically with each other. And
The four tip portions 19, 19 of the cross shaft 6 are respectively provided inside the first and second circular holes 15, 18 provided in pairs.
It is rotatably supported via bearings 20, 20 such as radial needle bearings.

The operation of the universal joint 1 incorporating the elastic shaft joint 7 constructed as described above is as follows. When the vehicle is in a straight-ahead state, or when the rotational torque applied to the shaft 2 from the steering wheel is small, the projecting pieces 9, 9 of the transmission piece 8 fixed to the tip of the shaft 2
Is the notch 1 formed in the cylindrical portion 13 of the first yoke 4
It is located at the inner neutral position of 6, 16 or at a position slightly offset from this neutral position. In each of these states, there is no direct contact between the cylindrical portion 13 and the transmission piece 8.
In addition, the small rotation torque is transmitted through the shock absorber cylinder 3,
The power is transmitted from the shaft 2 to the first yoke 4. In this case, the vibration transmitted from the wheel to the first yoke 4 via the steering gear, the another shaft, the second yoke 5, the cross shaft 6, and the like is applied to the elastic member 10 constituting the buffer cylinder 3.
And is not transmitted to the shaft 2.

On the other hand, when a large steering angle is applied to the front wheels, the shaft 2
If the rotational torque applied to the notch is large, the protruding pieces 9 abut against the inner surfaces of the notches 16. As a result, most of the rotational torque applied to the shaft 2 from the steering wheel is transmitted to the first yoke 4 via the transmission piece 8. In this state, the rotational torque transmitted via the buffer cylinder 3 is limited. Therefore, even when the rotational torque transmitted through the elastic shaft coupling 7 increases, no excessive force acts on the elastic member 10 constituting the buffer cylinder 3,
The elastic member 10 is not damaged.

[0010] As another example of the stopper portion forming the elastic shaft coupling, Japanese Utility Model Publication No. 7-43494 discloses FIG.
Are described. In the case of the elastic shaft coupling 7a described in this publication, the stopper portion is formed by a pair of through holes 21 and 21 (diameter D) formed at two positions on the diametrically opposite side of the cylindrical portion 13 constituting the first yoke 4. ), The ends {diameter d (<D)} of the cylindrical pin 22 supported and fixed to the tip of the shaft 2 are loosely engaged with each other. In addition, a pair of insertion holes 2 for inserting the near-end portions of the pin 22 at two diametrically opposite positions of the buffer cylinder 3 externally fitted and fixed to the tip end of the shaft 2.
3 and 23 are formed. Also in the case of such an elastic shaft coupling 7a, both ends of the pin 22 abut against the inner peripheral surfaces of the through holes 21 only when the rotational torque applied to the shaft 2 from the steering wheel is large. It prevents the elastic member 10 constituting the cushioning cylinder 3 from being acted on by a force that may lead to breakage.

[0011]

In order to improve the vibration absorbing performance of the elastic shaft couplings 7 and 7a as described above, the rigidity of the elastic material 10 constituting the shock-absorbing cylinder 3 must be appropriately adjusted. To the extent that the vibration absorption performance of the
It is necessary to make the elastic member 10 small enough to absorb the vibration transmitted from the steering gear. However,
In each of the conventional structures shown in FIGS. 4 to 5 and FIG. 6, the elastic member 10 constituting the cushioning cylinder 3 is replaced by the outer peripheral surface of the inner sleeve 11 constituting the cushioning cylinder 3 and the outer sleeve. 12 (except for the portion where the pair of insertion holes 23, 23 are formed in the case of the conventional structure shown in FIG. 6), it is tightly held (filled). For this reason, it is difficult to reduce the rigidity of the elastic member 10 appropriately, and it is difficult to improve the vibration absorbing performance of the elastic shaft couplings 7 and 7a.
The rigidity can be reduced by reducing the axial dimension of the buffer cylinder 3 or increasing the radial thickness of the elastic member 10. However, such a method may not be adopted because it is necessary to change the dimensions of other constituent members or the size may be increased. The elastic shaft coupling of the present invention has been invented in view of the above situation.

[0012]

The elastic shaft coupling of the present invention comprises:
An end of a rotatable shaft such as a steering shaft and a cylindrical member that rotates with the rotation of the shaft, such as a part of a yoke constituting a universal joint, are slightly displaced in the axial direction and the rotational direction. It is connected so that it can be absorbed. With such an elastic shaft coupling of the present invention, at least a circumferential displacement with respect to the end of the shaft is prevented when the outer sleeve is fixed to the tubular member and the end of the shaft is fitted to the end of the shaft. An inner sleeve, an elastic material held and fixed between an outer peripheral surface of the inner sleeve and an inner peripheral surface of the outer sleeve, and a shaft provided between an end of the shaft and the tubular member. A stopper that allows a slight displacement in the axial direction and the rotating direction between the end of the cylindrical member and the cylindrical member, but prevents a displacement in the rotating direction exceeding a predetermined angle, which may lead to damage of the elastic material. . Further, the rigidity of the elastic material is reduced by providing a recess or a hole in a part of the elastic material. The degree of reducing the rigidity of the elastic material depends on the shape of the recess or hole,
It is adjusted by selecting the size, the forming position, and the like.

[0013]

As described above, in the case of the elastic shaft coupling of the present invention,
The rigidity of the elastic material held between the inner and outer sleeves is appropriately adjusted (the rigidity of the elastic material becomes too low, and it is possible to prevent the components of the stopper portion from abutting each other when torque is not transmitted or when low torque is transmitted. And the vibration absorption performance can be reduced to such an extent that it does not decrease. Therefore, vibration can be sufficiently absorbed by this elastic material. Therefore, an elastic shaft coupling having excellent vibration absorbing performance can be realized. In addition, since the sizes of the inner sleeve and the outer sleeve are not different from the conventional ones, the above-described vibration absorbing performance can be improved without changing the size of other constituent members or increasing the size.

[0014]

FIG. 1 shows a first embodiment of the present invention. The feature of the present invention lies in the structure of the elastic member 10a constituting the buffer cylinder 3a. The structure and operation of the elastic shaft coupling including the shock-absorbing cylinder 3a are known from the conventional structure shown in FIGS. 4 to 5 and FIG. 6 described above, or another conventional art including the shock-absorbing cylinder. It is the same as the elastic shaft coupling. For this reason, illustration and description of parts other than the buffer cylinder 3a are omitted or simplified, and the following description focuses on the characteristic parts of the present invention.

The buffer cylinder 3a constituting the elastic shaft coupling of this embodiment
Is formed in a cylindrical shape including an elastic material 10a such as an elastomer such as rubber. That is, in the shock-absorbing cylinder 3a, the inner sleeve 11 and the outer sleeve 12, each made of metal and made in a cylindrical shape, are arranged concentrically with each other. The outer peripheral surface of the inner sleeve 11 and the elastic member 10a
And the inner peripheral surface of the elastic member 10a is similarly coupled to the inner peripheral surface of the outer sleeve 12 by baking or bonding.

Particularly, in the case of the present embodiment, concave portions 24, 24 each having a circular cross section are provided at a plurality of circumferential positions (in the illustrated example, at equal circumferential positions) on both axial end surfaces of the elastic member 10a.
Are formed in the axial direction, respectively. Further, in the case of the illustrated example, the circumferential phases of the concave portions 24, 24 are matched on both axial sides of the elastic member 10a. Then, by forming these concave portions 24, 24 and reducing the volume of the elastic member 10a, the rigidity of the elastic member 10a is appropriately adjusted (to such an extent that the vibration absorbing performance of the elastic member 10a does not decrease. ) Small. In addition, each said recess 2
4 and 24 are formed, for example, simultaneously with the injection molding of the elastic material 10a. In the case of the present embodiment in which the recesses 24, 24 are formed as described above, the torsional rigidity (in the circumferential direction) of the elastic member 10a can be sufficiently reduced.

The cushioning cylinder 3a constructed as described above has a cylinder in which the inner sleeve 11 is externally fitted and fixed to the tip of the shaft 2 (see FIGS. 4 and 6), and the outer sleeve 12 is provided on the first yoke 4. By being internally fitted and fixed to the portion 13 (see FIGS. 4 and 6), it is incorporated as a constituent member of the elastic shaft coupling. Note that the shock-absorbing cylinder 3a of this example is replaced with the elastic shaft coupling 7 having the structure shown in FIG.
In the case of assembling into the buffer cylinder 3a, a pair of insertion holes 23, 23 (see FIG. 6) for inserting the portions near both ends of the pin 20 are formed at two positions on the opposite side in the diameter direction of the buffer cylinder 3a.

The function of absorbing the vibration by the elastic shaft coupling of the present embodiment configured as described above is the same as that of the conventional structure described above. In particular, in the case of the elastic shaft coupling according to the present embodiment, the size of the shock-absorbing cylinder 3a is kept unchanged, other components can be used as they are, and the elastic member 10a held between the inner and outer sleeves 11 and 12 is used. Can be reduced in rigidity appropriately. The elastic member 10a can sufficiently absorb the vibration transmitted from the steering gear. Therefore, an elastic shaft coupling having excellent vibration absorbing performance can be realized.

FIG. 2 shows a second embodiment of the present invention.
An example is shown. In the case of the present example, the cross-sectional shapes of the plurality of concave portions 24a, 24a provided on both end surfaces in the axial direction of the elastic member 10b constituting the shock-absorbing cylinder 3b are arc-shaped. Other configurations and operations are the same as those of the above-described first example.

Next, FIG. 3 shows a third embodiment of the present invention.
An example is shown. In the case of this example, circular holes 25, 25 having a circular cross section are respectively formed at a plurality of positions in the circumferential direction of the elastic member 10c constituting the shock-absorbing cylinder 3c (in the illustrated example, at equal circumferential positions). It is formed in the axial direction so that both end faces communicate with each other. Then, by forming these holes 25, 25, and reducing the volume of the elastic material 10c,
The rigidity of the elastic member 10c is appropriately reduced (to the extent that the vibration absorbing performance of the elastic member 10c does not decrease). Incidentally, also in the case of this example, the cross-sectional shape of each of the holes 25, 25 may be an arc. Other configurations and operations are the same as in the case of the above-described first example.

In each of the above-described examples, the buffer cylinders 3a to 3c
Although the inner and outer sleeves 11 and 12 are simply cylindrical, the shape of each of these sleeves can be any suitable shape such as an oval shape according to the structure of the elastic shaft coupling. Also, the shape of the recess or hole provided in the elastic material,
The size and the forming position can also be appropriately set so that the rigidity of the target elastic material can be appropriately reduced.

[0022]

The elastic shaft coupling according to the present invention is constructed and operated as described above, so that the elastic material constituting the shock-absorbing cylinder can sufficiently absorb vibration. Therefore, an elastic shaft coupling having excellent vibration absorbing performance can be realized.

[Brief description of the drawings]

1A and 1B show a shock-absorbing cylinder constituting a first example of an embodiment of the present invention, wherein FIG. 1A is a cross-sectional view, and FIG.
a sectional drawing.

FIG. 2 is a view similar to FIG. 1, showing the second example;

FIG. 3 is a view similar to FIG. 1, showing the third example;

FIG. 4 incorporates a first example of a conventional structure of an elastic shaft coupling;
FIG. 4 is a partial cross-sectional view of a universal joint.

FIG. 5 is a sectional view taken along line bb of FIG. 4;

FIG. 6 incorporates a second example of the conventional structure of the elastic shaft coupling;
FIG. 4 is a partial cross-sectional view of a universal joint.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 universal joint 2 shaft 3, 3 a, 3 b, 3 c buffer cylinder 4 first yoke 5 second yoke 6 cross shaft 7, 7 a elastic shaft coupling 8 transmission piece 9 protruding piece 10, 10 a, 10 b, 10 c elastic material 11 inner sleeve DESCRIPTION OF SYMBOLS 12 Outer sleeve 13 Cylindrical part 14 First arm 15 First circular hole 16 Notch 17 Second arm 18 Second circular hole 19 Tip part 20 Bearing 21 Through hole 22 Pin 23 Insertion hole 24, 24a Concave 25 hole

Claims (1)

[Claims] An elastic shaft coupling for connecting an end of a rotatable shaft and a cylindrical member that rotates with the rotation of the shaft so as to absorb a slight displacement in an axial direction and a rotational direction, An outer sleeve fixed to the cylindrical member, an inner sleeve that is fitted to an end of the shaft and is prevented from being displaced at least in a circumferential direction with respect to an end of the shaft, and an outer peripheral surface of the inner sleeve An elastic material held and fixed between the shaft and the inner peripheral surface of the outer sleeve; and an elastic member provided between an end of the shaft and the cylindrical member, and an axial direction between the end of the shaft and the cylindrical member. And a stopper portion for allowing a slight displacement in the rotation direction, but for preventing a displacement in the rotation direction exceeding a predetermined angle, which may lead to damage to the elastic material, further comprising a recess in a part of the elastic material. Or by providing a hole An elastic shaft coupling that reduces the rigidity of the elastic material.